PIC18F25J10-I/SS Microchip Technology, PIC18F25J10-I/SS Datasheet - Page 65

• Manufacturer Part Number: PIC18F25J10-I/SS
• Description: IC PIC MCU FLASH 16KX16 28SSOP
• Manufacturer: Microchip Technology
• Series: PIC® 18Fr

Specifications of PIC18F25J10-I/SS

• Core Size: 8-Bit
• Program Memory Size: 32KB (16K x 16)
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Core Processor: PIC
• Speed: 40MHz
• Connectivity: I²C, SPI, UART/USART
• Number Of I /o: 21
• Program Memory Type: FLASH
• Ram Size: 1K x 8
• Voltage - Supply (vcc/vdd): 2.7 V ~ 3.6 V
• Data Converters: A/D 10x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 28-SSOP
• Controller Family/series: PIC18
• No. Of I/o's: 21
• Ram Memory Size: 1KB
• Cpu Speed: 40MHz
• No. Of Timers: 3
• Processor Series: PIC18F
• Core: PIC
• Data Bus Width: 8 bit
• Data Ram Size: 1 KB
• Interface Type: SPIC, I2C, EUSART
• Maximum Clock Frequency: 40 MHz
• Number Of Programmable I/os: 21
• Number Of Timers: 3
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• 3rd Party Development Tools: 52715-96, 52716-328, 52717-734, 52712-325, EWPIC18
• Development Tools By Supplier: PG164130, DV164035, DV244005, DV164005, PG164120, DM183022, DM183032, DV164136
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 10 bit, 10 Channel
• Package: 28SSOP
• Device Core: PIC
• Family Name: PIC18
• Maximum Speed: 40 MHz
• Operating Supply Voltage: 5 V
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With: AC162074 - HEADER INTRFC MPLAB ICD2 44TQFPMA180011 - MODULE PLUG-IN 18F25J10 28SOICAC162067 - HEADER INTRFC MPLAB ICD2 40/28PAC164331 - MODULE SKT FOR 28SSOP 18F45J10XLT28SS-1 - SOCKET TRANSITION ICE 28SSOP
• Eeprom Size: -
• Lead Free Status / Rohs Status: Details

5.4.3.1
At the core of Indirect Addressing are three sets of reg-
isters: FSR0, FSR1 and FSR2. Each represents a pair
of 8-bit registers, FSRnH and FSRnL. The four upper
bits of the FSRnH register are not used, so each FSR
pair holds a 12-bit value. This represents a value that
can address the entire range of the data memory in a
linear fashion. The FSR register pairs, then, serve as
pointers to data memory locations.
Indirect Addressing is accomplished with a set of
Indirect File Operands, INDF0 through INDF2. These
can be thought of as “virtual” registers; they are
mapped in the SFR space but are not physically imple-
mented. Reading or writing to a particular INDF register
actually accesses its corresponding FSR register pair.
A read from INDF1, for example, reads the data at the
address indicated by FSR1H:FSR1L. Instructions that
use the INDF registers as operands actually use the
contents of their corresponding FSR as a pointer to the
instruction’s target. The INDF operand is just a
convenient way of using the pointer.
Because Indirect Addressing uses a full 12-bit address,
data RAM banking is not necessary. Thus, the current
contents of the BSR and the Access RAM bit have no
effect on determining the target address.
FIGURE 5-8:
© 2008 Microchip Technology Inc.
Using an instruction with one of the
Indirect Addressing registers as the
operand....
...uses the 12-bit address stored in
the FSR pair associated with that
register....
...to determine the data memory
location to be used in that operation.
In this case, the FSR1 pair contains
ECCh. This means the contents of
location ECCh will be added to that
of the W register and stored back in
ECCh.
FSR Registers and the INDF
Operand
INDIRECT ADDRESSING
x x x x 1 1 1 0
7
ADDWF, INDF1, 1
FSR1H:FSR1L
0
7
1 1 0 0 1 1 0 0
PIC18F45J10 FAMILY
5.4.3.2
In addition to the INDF operand, each FSR register pair
also has four additional indirect operands. Like INDF,
these are “virtual” registers that cannot be indirectly
read or written to. Accessing these registers actually
accesses the associated FSR register pair, but also
performs a specific action on it stored value. They are:
• POSTDEC: accesses the FSR value, then
• POSTINC: accesses the FSR value, then
• PREINC: increments the FSR value by 1, then
• PLUSW: adds the signed value of the W register
In this context, accessing an INDF register uses the
value in the FSR registers without changing them. Sim-
ilarly, accessing a PLUSW register gives the FSR value
offset by that in the W register; neither value is actually
changed in the operation. Accessing the other virtual
registers changes the value of the FSR registers.
Operations on the FSRs with POSTDEC, POSTINC
and PREINC affect the entire register pair; that is, roll-
overs of the FSRnL register, from FFh to 00h, carry
over to the FSRnH register. On the other hand, results
of these operations do not change the value of any
flags in the STATUS register (e.g., Z, N, OV, etc.).
automatically decrements it by 1 afterwards
automatically increments it by 1 afterwards
uses it in the operation
(range of -127 to 128) to that of the FSR and uses
the new value in the operation.
FSR Registers and POSTINC,
POSTDEC, PREINC and PLUSW
0
FFFh
E00h
000h
100h
200h
300h
F00h
Data Memory
Bank 13
Bank 14
Bank 15
through
DS39682D-page 63
Bank 0
Bank 1
Bank 2
Bank 3